I would like to search within an individual email message using OS X Mail version 5.3 or above (Lion, Mountain Lion). I would like this search to include the email header.
Using the menu item
Edit > Find > Find… or
Command-F via the keyboard I am able to search the entire message, exclusive of the header. I would like to search the header, also.
An example of how this would be used: An email message is sent to hundreds of recipients which you want to search to find a specific email address.